K1 / K2 spring kit

[IslandMon]

1 turn on the full throttle valve set screw didn’t solve the 1-2 upshift problem, still bouncing off the rev limiter. I almost tried 2 turns but figured I should follow the FSM recommendation. I guess I’ll drop the pan and try 1 more full turn, and hope that does it.

While i had the pan off I installed the smaller inner spring into the new red K2. I didn’t feel any difference in the 3-4 shift, but it felt fine before so Don’t really care.

before I did all that I shortened the Bowden rod to try to lower the rpm of the 1-2 shift, that didn’t do anything either…

Wish there were results for my efforts, but more pan dropping ahead I guess. Stay tuned

 

[IslandMon]

Dropped the pan and valve body and turned the full throttle valve screw 1 more turn clockwise after taking the plate off and checking the springs in there. Unfortunately I’m still bouncing off the rev limiter with WOT kickdown after the trans is hot.

For the late 1-2 upshift Superior told me to revert the step 6 spring to the original, and then revert the step 8 if that doesn’t work. Neither worked so I’m going to revert the step 7 springs as well, since they are the last ones related to the 1-2 shift. If that doesn’t work, Im going to install the 2nd gear start valve body that came with the sun valley rebuild, to make sure the shifting is normal with a stock valve body.

I think I’m on pan drop 3… getting quicker each time

 

[IslandMon]

Reverted the step 7 spring to factory and both problems persist…

I tried shortening the rod for the Bowden cable, which mis-aligns the pointers, but it didn’t seem to reduce the 1-2 upshift RPM much at all. The other shifts seem OK.

I guess next step is putting the original sun valley SGS valve body in and seeing if either of the problems persist.

onto pan drop #5…

I’ve been using three 125 micron paint filters stacked into my funnel for each fluid swap and have been catching very tiny particulate each time.

 

[IslandMon]

Installed the SGS valve body today, with a brand new K1 spring kit, and both problems are gone. The shifts are all nice and firm and timed well.

I’ll need to talk to Jim at Superior tomorrow to see which other springs he thinks could have caused the issues in the FGS valve body.

Happy to have a working box, and tired of dropping the pan, so I think I’m going to leave this valve body in for the summer.
Any future work on this will be on my owners thread.

 

[gsxr]

Thanks for the info, IslandMon! To clarify - you did not have the "rev limiter" problem before intsalling the Superior kit, correct? I'm really interested to find out what caused this, especially since you could not adjust it to fix the problem.

 

[IslandMon]

To clarify - you did not have the "rev limiter" problem before intsalling the Superior kit, correct?

I honestly don’t know because I didn’t perform WOT kick down takeoffs ever. I now know what I was missing out on though.

Before the superior kit the only issues were a hard 1-2 shift at a reasonable RPM, and a flaring 2-3.

Worth noting that I did see 12.7 Ohms of resistance on the kickdown solenoid.

More fiddling with the full throttle valve set screw, or reverting more springs back to factory might fix the FGS valve body, but I certainly won’t be messing around with it soon.

 

[gsxr]

I honestly don’t know because I didn’t perform WOT kick down takeoffs ever. I now know what I was missing out on though.

Before the superior kit the only issues were a hard 1-2 shift at a reasonable RPM, and a flaring 2-3.

Worth noting that I did see 12.7 Ohms of resistance on the kickdown solenoid.

More fiddling with the full throttle valve set screw, or reverting more springs back to factory might fix the FGS valve body, but I certainly won’t be messing around with it soon.

Understood. Since the different VB is behaving as expected, your kickdown solenoid is likely working normally. Something is wonky with the VB.

I have a VB that was doing something similar years ago, and after fiddling with it like you did, I eventually gave up and swapped in a different VB. Only the 1-2 upshift was affected, and only at WOT. It's almost like the 1-2 shift occurs too slowly, but I don't know what the cause is, nor remedy. I've wondered if fully disassembling and cleaning the VB might help, but that's many hours of tedious work...

 

[mstar1]

There have been some changes to the springs through the years. Some of those springs were in a TSB on our ng, some are for 722.4xx, and some address specific issues. The K2 is the example there. There is a superior shift kit available for ~ $45. It has several options for making the shifts firmer or softer.

Those kits are the accumulator kits. I went through last year and ordered every one available and experimented. No notes in my hand- but I believe for most(unless you have a broken spring), that you can replace the K2(effecting 2-->3 shift) and move the old K2 into the K1 position. Monkeying with the shift kit plan on removing and changing springs 2 or 3 times. K1 and K2 are on either ends of the same spool. So changing one effects the other...

You can turn up the pressure slightly which will quicken shifting. Clean fluid will improve shifting.

Is it worth replacing them? If you are not experiencing a problem- don't touch it. If you want to improve something- please give us more details on how it is shifting.

I have a W140 600SEL that has started to have a flare between the 2-3 shift. It only happens before the transmission gets to operating temperature (9-10 miles with summer temperatures, I expect it will be take longer during the colder winter season). So I am planning on getting a transmission service using Redline D4 ATF.

I have purchased the K1 kit ( pt# 126 270 44 77) and the valve body kit ( pt# 126 270 03 35). I understand that the theory is that the original spring has weakened over time and use and the updated K1 spring improves the shift quality because it is a stronger big spring and the weaker short spring. And there is a possibility that the valve body is gummed up and/or the seals have lost some of their integrity. I have also read that the greatest improvement may be obtained from replacing the valve body with the updated K1 spring kit.

My question is what are the perceived advantages/disadvantages to just using the new valve body kit with the original new springs that come with the kit and not using the updated K1 spring kit. Thanks in advance for your opinion

 

[gsxr]

I have purchased the K1 kit ( pt# 126 270 44 77) and the valve body kit ( pt# 126 270 03 35). I understand that the theory is that the original spring has weakened over time and use and the updated K1 spring improves the shift quality because it is a stronger big spring and the weaker short spring. And there is a possibility that the valve body is gummed up and/or the seals have lost some of their integrity. I have also read that the greatest improvement may be obtained from replacing the valve body with the updated K1 spring kit.

Make sure to use the #44 springs with the #03 kit green piston. Discard the springs that come with the green piston, as noted back in post #32 earlier in this thread.

My question is what are the perceived advantages/disadvantages to just using the new valve body kit with the original new springs that come with the kit and not using the updated K1 spring kit. Thanks in advance for your opinion

The new green piston won't make much difference. The #44 springs should help eliminate the flare during the 2-3 upshift at part throttle. Use both the green piston AND the #44 springs.

If a slight flare remains, you can adjust the vacuum modulator firmer, as long as other shifts are not excessively firm or harsh. The modulator will make all shifts firmer (or softer, if you adjust in the opposite direction).

Welcome to the forum!